I've been on to the data protection people and they say that for people using work computers there may be an issue but only if offensive material was being accessed or distributed or if the work computers were used in facilitating bullying. I think we're all safe on that so
Unless the IAA state that in their acceptable usage policy that pprune or similiar sites are forbidden they cannot object to staff posting on such sites. For those of us that only access pprune from our homes and personal machines they cant do a thing.
It sounds to me as if this is just posturing from the IAA and I would guess that they know their arses are out the window with their accusations of "orchestrated sick leave" so in their puny minds they they think they'll find evidence of that conspiracy here.
If you've been posting from work you're covered by Data Protection and are not obliged to confirm or deny your identity, it's up to them to prove malpractice.
If you post from home you can tell them to F**K right off! and that by even asking you about your activities on this site they are in breach of a whole raft of privacy legislation.
Stay Happy, focussed and united!
We beat them and this nonsense is the death throes of a bitter and vindictive employer still looking to villify the staff